1. Field of the Invention
The invention resides in the field of fastening devices and more particularly relates to a cam-shaped member in contact with a post, which cam is rotated to reduce the distance between the two plates.
2. Description of the Prior Art
The best-known example of a rotatable cam in contact with a post for drawing two plates or surfaces together is the nut and bolt. In that device, a circular ramp or thread is cut on the outside of the bolt and a matching thread is formed on the outside of the nut. The nut fits over the bolt and presses against one of the plates which the bolt passes through, the bolt being attached to the other of the plates to be fastened. As the nut is rotated, the bolt is forced forward or backward drawing the plates together, or, alternatively, releasing them.
The variations of this basic concept are so extensive and well-known that further elaboration is unnecessary. In contrast, the present invention employs a rotatable ramp which is positioned to one side of slotted post and is arranged to engage the slot such that upon rotation of the ramp the post is forced forward or backward in a manner akin to the function of the nut and bolt. For particular applications there are substantial advantages to this arrangement over the traditional nut and bolt.
For example, when used in a corrosive environment, the risk of seizing, as might more readily occur with threaded nuts and bolts, is reduced.
The likelihood of cross-threading and consequential stripping or jamming is eliminated.
As the ramp members are attached to one of the plates they cannot get misplaced or dropped.
In biological applications, where a low level of contamination is important, the elimination of threads reduces the surfaces where undesirable materials might accumulate. Further, smooth posts allow an easier insertion of gaskets or similar devices between the plates when the posts are used as alignment guides.
These and other features and advantages of the invention will become more apparent from the detailed description below.